1. Field of the Invention
The present invention relates to a photoreceptor unit to form an image to be transferred onto a transfer medium.
2. Description of the Related Art
As is generally known in the art, a printing machine, such as a laser printer or a photocopier, comprises a photoreceptor unit for the development of images.
A photoreceptor unit is valid during a limited period of time and is required to be replaced at the end of its life cycle in order to develop and produce clean images. For the facilitation of the replacement, a photoreceptor unit is generally modularized to be replaced as a whole with a new one.
A modularized photoreceptor unit may include a photoconductive drum assembly, a housing for enclosing and protecting part of the photoconductive drum assembly and a handgrip.
The photoreceptor unit may additionally include a charging unit, a cleaning unit and a used toner recovering unit.
The photoreceptor unit should expose a photoconductive drum to face a developer unit for the development of toner images. The other units, such as the charging unit, the cleaning unit and the used toner recovering unit, should be placed on an opposite side of the photoconductive drum with respect to the developer unit not to face the developer unit. Accordingly, the photoreceptor unit has a center of gravity displaced from a center of rotation of the photoconductive drum.
The handgrip is provided to be used when the modularized photoreceptor unit is mounted into or separated from a printer mainframe. A user can mount the photoreceptor unit into the printer mainframe using the handgrip. Also, the user can pull out the photoreceptor unit from the printer mainframe using the handgrip.
However, if the handgrip is not provided at the center of gravity of the photoreceptor unit, it will be difficult for the user to lift up or move the photoreceptor unit with one hand. If the handgrip is rotatably formed, the photoreceptor unit will be lopsided toward its center of gravity. Thus, the user has to hold the photoreceptor unit with both hands.
It is also likely that the photoreceptor unit may be mounted into the printer mainframe in a lopsided condition. As a result, the photoconductive drum or the printer mainframe may be damaged during the mounting of the photoreceptor unit.